When we deal with applications where strength-to-weight ratio is a critical consideration, we often turn to solutions involving the so-called “light metals.” Aluminum, magnesium, titanium and in some cases beryllium enhance engineering performance while minimizing the weight of components and structures. Most of us involved in heat treating these materials know how we do it, but it is equally important to understand why we do it. By Daniel H. Herring

Stainless steels are widely used in the chemical, petrochemical and food-processing industries due to their favorable corrosion properties. The industrial world would not exist without this class of material.[1] They exhibit generally poor tribological properties, however, which limit their applications to use in tribocorrosive environments. By Luiz Carlos Casteletti, Amadeu Lombardi Neto, G.E. Totten

This article outlines the furnace operation and maintenance requirements of AMS 2750D, with particular focus on how these requirements have changed from AMS 2750C and how proof of compliance can be achieved. By Richard Bolton

When it comes to understanding any subject, and in particular heat treating, having reference material you can trust is invaluable. Over the years we have talked with a number of extremely knowledgeable heat treaters and metallurgists and from these discussions, we have compiled the following list of our “favorites.” Newer editions may exist, but exercise caution to ensure their contents are equal to or better than the originals. No heat treat library is complete without them. By Daniel H. Herring

When we talk in terms of heat treating in vacuum, most people think we do so in a space entirely devoid of matter. In reality, this isn’t true. In practical terms then, a vacuum is a space with a highly reduced gas density. Just how many gas molecules are still present and how they react inside the vacuum furnace is something we should better understand. By Daniel H. Herring

While the end-use application of a component dictates its heat treatment, as heat treaters we know that we must achieve a delicate balance between the properties of strength and ductility. Nowhere is this fine line more evident than in the tempering process where precise control of time and temperature are critical to help produce a part with optimized microstructure and mechanical properties. Essentially, tempering is the modification of this newly formed microstructure toward equilibrium. Almost all steels that are subjected to any type of hardening process are tempered. A temper is a subcritical heat treatment that alters the microstructure and properties. In general, tempering lowers strength and hardness while improving ductility and toughness of the as-quenched martensite. However, this is not always the case. By Daniel H. Herring

Heat treating of stainless steels depends to a great extent on the type (wrought or cast) and grade of stainless steel, as well as the reason for the treatment, most often to ensure that the properties altered during fabrication are restored (e.g. corrosion resistance, ductility, or hardness) so that the stainless steel component can perform in its intended service environment. There are quite a variety of different heat treatments available. By Daniel H. Herring